There is no hard and fast clinical standard for how much of the tooth needs to be staked. However, in most cases, the following five cases need to be staked: 1, most of the missing clinical crowns can not be directly applied to crown restoration or inlay restoration; 2, the remaining tooth tissue after root canal treatment is too little, there is a tendency to split the person at this time need to play a staking; 3, the clinical crown is completely missing, the section reaches the subgingival, but there is sufficient length of the root, can be through the crown lengthening or traction surgery, expose the section of the following at least 1.5mm root surface height, grinding teeth to not expose the root bifurcation limit, then can be retained through the pile core crown to retain the tooth; 4, misaligned torsion of the tooth and not orthodontic indications; 5, malocclusion of the tooth direct preparation, poor retention can be restored through the pile core crown to increase retention to ensure the restoration effect.